Golf club head

ABSTRACT

A golf club head is described having a club head portion, a shaft portion connected to the club head portion, and a grip portion connected to the shaft portion. The club head portion has a heel portion, a sole portion, a toe portion, a crown portion, a hosel portion, and a striking face. The striking face has a center face roll contour, a toe side roll contour, a heel side roll contour, a center face bulge contour, a crown side bulge contour, and a sole side bulge contour. The toe side roll contour is more lofted than the center face roll contour. The heel side roll contour is less lofted than the center face roll contour. The crown side bulge contour is more open than the center face bulge contour, and the sole side bulge contour is more closed than the center face bulge contour.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/811,430, filed on Nov. 13, 2017, which is a continuation of U.S.patent application Ser. No. 15/199,603, filed on Jun. 30, 2016, now U.S.Pat. No. 9,814,944, both of which are incorporated herein by referencein their entirety.

FIELD

The present disclosure relates to a golf club head. More specifically,the present disclosure relates to a golf club head having a unique faceconstruction.

BACKGROUND

When a golf club head strikes a golf ball, a force is seen on the clubhead at the point of impact. If the point of impact is aligned with thecenter face of the golf club head in an area of the club face typicallycalled the sweet spot, then the force has minimal twisting or tumblingeffect on the golf club. However, if the point of impact is not alignedwith the center face, outside the sweet spot for example, then the forcecan cause the golf club head to twist around the center face. Thistwisting of the golf club head causes the golf ball to acquire spin. Forexample, if a typical right handed golfer hits the ball near the toe ofthe club this can cause the club to rotate clockwise when viewed fromthe top down. This in turn causes the golf ball to rotatecounter-clockwise which will ultimately result in the golf ball curvingto the left. This phenomenon is what is commonly referred to as “geareffect.”

Bulge and roll are golf club face properties that are generally used tocompensate for this gear effect. The term “bulge” on a golf clubtypically refers to the rounded properties of the golf club face fromthe heel to the toe of the club face.

The term “roll” on a golf club typically refers to the roundedproperties of the golf club face from the crown to the sole of the clubface. When the club face hits the ball, the ball acquires some degree ofbackspin. Typically this spin varies more for shots hit below the centerline of the club face than for shots hit above the center line of theclub face.

FIG. 1 illustrates the problem to be solved by the present invention.FIG. 1 shows a ball location with respect to the intended target whenthe golf ball is struck with a club having a constant bulge and rollradius. The nine rectangles indicate the ball location when struck inthe respective heel, toe, center, high, center, low combinations. Thefairway 124 is separated from the rough 126 by a fairway edge 120,122.The final ball location is shown with respect to an intended target line118. The intended target line 118 is the line along which the golf clubhead center is aimed when the golf is at the address position. When thegolf ball is struck in the high position, the golf ball tends to have a“left tendency” which means the ball's final resting position will beleft of the target line 118 As illustrated by points 100, 102, and 104shown in FIG. 1. When the golf ball is struck in the low position, thegolf ball tends to have a “right tendency” which means the ball's finalresting position will likely be to the right of the target line 118 asillustrated by points 112, 114,116 shown in FIG. 1. When a golf ballimpacts the ball in the central horizontal portion of the face, the balltends to come to rest on target relative to the target line 118 asillustrated by points 106,108,110 shown in FIG. 1.

A golf club design is needed to counteract the left and right tendencythat a player encounters when the ball impacts a high or low position onthe club head striking face.

SUMMARY OF THE DESCRIPTION

The present disclosure describes a golf club head comprising a heelportion, a toe portion, a crown, a sole, and a face.

The foregoing and other objects, features, and advantages of theinvention will become more apparent from the following detaileddescription, which proceeds with reference to the accompanying figures.

According to one aspect of an embodiment of the present invention, agolf club a club head portion having a hosel portion, a heel portion, asole portion, a toe portion, a crown portion, and a striking face isdescribed. The golf club further has a shaft portion connected to theclub head portion and a sleeve portion connected to the shaft portion.The sleeve portion is capable of adjusting the loft, lie, or face angleof the club head when removed from the hosel portion in a firstconfiguration and reinserted into the hosel portion in a secondconfiguration.

The golf club also has a grip portion connected to the shaft portion anda striking face having a center face location. A center face verticalplane passing through the center face location and intersecting with thestriking face surface to define a center face roll contour is alsodescribed. A toe side vertical plane being spaced away from the centerface vertical plane by 30 mm toward the toe portion and intersectingwith the striking face surface to define a toe side roll contour isdescribed.

A heel side vertical plane is described being spaced away from thecenter face vertical plane by 30 mm toward the heel portion andintersecting with the striking face surface to define a heel side rollcontour. Furthermore, a center face horizontal plane passing through thecenter face location and intersecting with the striking face surfacedefines a center face bulge contour. A crown side horizontal plane beingspaced away from the center face horizontal plane by 15 mm toward thecrown portion and intersecting with the striking face surface to definea crown side bulge contour is described in one embodiment. A sole sidehorizontal plane that is spaced away from the center face horizontalplane by 15 mm toward the sole portion and intersects with the strikingface surface to define a sole side bulge contour is describe.

In one embodiment, The toe side roll contour is more lofted than thecenter face roll contour. In yet another embodiment, the heel side rollcontour is less lofted than the center face roll contour. In someembodiments, the crown side bulge contour is more open than the centerface bulge contour. In certain embodiments described herein, the soleside bulge contour is more closed than the center face bulge contour.

In one embodiment, a point located at 20 mm above the center facelocation has a FA° Δ of between 0.1° and 4°. A point located at 20 mmabove the center face location having a FA° Δ of between 0.3° and 3° isalso described.

In one embodiment, a point located at 20 mm below the center facelocation has a FA° Δ of between −0.1° and −4°. A point located at 20 mmbelow the center face location having a FA° Δ of between −0.3° and −3°is further described.

In some embodiments, a critical point located at 15 mm above the centerface location has a LA° Δ that is substantially unchanged compared to a0° twist golf club head.

In yet another embodiment, a heel side point located at a x-y coordinateof (30 mm, 0 mm) has a LA° Δ relative to a center that is between 0° and−8°. In another embodiment, a toe side point located at a x-y coordinateof (−30 mm, 0 mm) has a LA° Δ relative to a center that is between 0°and 8°.

In one embodiment, the striking face has a degree of twist that isbetween 0.1° and 5° when measured between two critical locations locatedat 15 mm above the center face location and 15 mm below the center facelocation.

According to one aspect of another embodiment of the present invention,a golf club is described having a striking face with a center facelocation and four quadrants. The four quadrants comprise an upper toequadrant, an upper heel quadrant, a lower toe quadrant, and a lower heelquadrant. In one embodiment, the striking face is a twisted strikingsurface having a degree of twist wherein the upper toe quadrant, andupper heel quadrant have an average positive FA° Δ relative to a 0°twist golf club head.

In yet another embodiment, the lower toe quadrant and the lower heelquadrant that have an average FA° Δ that is negative relative to a 0°twist golf club head is described.

In one embodiment, the degree of twist is greater than 0° when measuredbetween two critical locations located at 15 mm above the center facelocation and 15 mm below the center face location.

In another embodiment, the degree of twist is between 0.1° and 5° whenmeasured between two critical locations located at 15 mm above thecenter face location and 15 mm below the center face location.

In yet another embodiment, the upper toe quadrant has an average FA° Δof between 0.1° to 0.8° and the upper heel quadrant has an average FA° Δof between 0.1° to 0.8°.

In one embodiment, the lower toe quadrant has an average FA° Δ ofbetween −0.1° to −0.8° and the lower heel quadrant has an average FA° Δof between −0.1° to −0.8°. According to one aspect of another embodimentof the present invention, a golf club is described having a club headportion, a shaft portion connected to the club head portion, and a gripportion connected to the shaft portion. The club head portion has a heelportion, a sole portion, a toe portion, a crown portion, a hoselportion, and a striking face. The striking face has a striking facesurface, a center face point, a x-axis that is tangent to the centerface point and is parallel to a ground plane extending in a heel-wardpositive direction, and a y-axis that is tangent to the center facepoint and extending in an upwards positive direction toward the crown.The y-axis has a downwards negative direction toward the sole.

A plurality of points measured on the striking face surface along they-axis having a FA° Δ rate of change is described. The FA° Δ rate ofchange is greater than zero.

In one embodiment, the FA° Δ rate of change is between 0.005° Δ/mm and0.2° Δ/mm.

In another embodiment, a plurality of points measured on the strikingsurface along the x-axis having a LA° Δ rate of change that is between−0.005° Δ/mm and −0.2° Δ/mm is described.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is illustrated by way of example and notlimitation in the figures of the accompanying drawings in which likereferences indicate similar elements.

FIG. 1 is an illustration of different ball locations relative to theimpact location on a golf club face.

FIG. 2a is an elevated front view of a golf club head.

FIG. 2b is a sole view of a golf club head.

FIG. 2c is an isometric cross-sectional view taken along section lines 2c-2 c in FIG. 2 b.

FIG. 2d is a top view of a golf club head.

FIG. 2e is an elevated heel perspective view of a golf club head.

FIG. 2f is a cross-sectional view taken along section lines 2 f-2 f inFIG. 2 d.

FIG. 3 is an isometric view of a shaft tip sleeve.

FIG. 4a is an elevated front view of a golf club according to anembodiment.

FIG. 4b is an exaggerated comparative view of face surface contourstaken along section lines A-A, BB, and C-C as seen from a heel view.

FIG. 4c is an exaggerated comparative view of face surface contourstaken along section lines D-D, E-E, and F-F as seen from a top view.

FIG. 5 is a front view of a golf club face with multiple measurementpoints and four quadrants.

FIG. 6a is an isometric view of an exemplary twisted face surface plane.

FIG. 6b is a top view of an exemplary twisted face surface plane.

FIG. 6c is an elevated heel view of an exemplary twisted face surfaceplane.

FIG. 7 illustrates a front view of a golf club with a predetermined setof measurement points.

FIG. 8 illustrates a front view of a golf club with a predetermined setof measurement points.

FIG. 9 is a graph showing a FA° Δ along a y-axis location.

FIG. 10 is a graph showing a LA° Δ along a x-axis location.

DETAILED DESCRIPTION

Various embodiments and aspects of the inventions will be described withreference to details discussed below, and the accompanying drawings willillustrate the various embodiments. The following description anddrawings are illustrative of the invention and are not to be construedas limiting the invention. Numerous specific details are described toprovide a thorough understanding of various embodiments of the presentinvention. However, in certain instances, well-known or conventionaldetails are not described in order to provide a concise discussion ofembodiments of the present inventions.

FIG. 2a illustrates a golf club head having a front portion 204, a heelportion 200, a toe portion 210, a crown portion 218, a hosel portion248, a sole portion 208, a hosel axis 214, a lie angle 228, and a hoselinsert 212. The golf club head has a width dimension W, a heightdimension H, and a depth dimension D measured when the golf club head ispositioned in an address position. The address position is defined asthe golf club head in a lie angle of fifty-seven degrees and the loft ofthe club adjusted to the designated loft of the club head. Unlessotherwise stated, all the measured dimensions described herein areevaluated when the club head is oriented in the address position. If theclub head at a fifty-seven degree lie angle visually appears to beunlevel from a front face perspective, an alternative lie angle calledthe “scoreline lie” may be used. The scoreline lie is defined as the lieangle at which the substantially horizontal face scorelines are parallelto a perfectly flat ground plane. The width dimension W is not greaterthan 5 inches, and the depth dimension D is not greater than the widthdimension W. The height dimension H is not greater than 2.8 inches. Insome embodiments, the depth dimension D or the width dimension W is lessthan 4.4″, less than 4.5″, less than 4.6″, less than 4.7″, less than4.8″, less than 4.9″, or less than 5″. In some embodiments the heightdimension H is less than 2.7″, less than 2.6″, less than 2.5″, less than2.4″, less than 2.3″, less than 2.2″, less than 2.1″, less than 2″, lessthan 1.9″ or less than 1.8″. In certain embodiments, the club headheight is between about 63.5 mm to 71 mm (2.5″ to 2.8″) and the width isbetween about 116.84 mm to about 127 mm (4.6″ to 5.0″). Furthermore, thedepth dimension is between about 111.76 mm to about 127 mm (4.4″ to5.0″).

These dimensions are measured on horizontal lines between verticalprojections of the outermost points of the heel and toe, face and back,and sole and crown. The outermost point of the heel is defined as thepoint on the heel that is 0.875″ above the horizontal ground plane 202.

FIG. 2a further illustrates a face center 220 location. This location isfound by utilizing the USGA Procedure for Measuring the Flexibility of aGolf Clubhead, Revision 2.0 published on March 25, 2005, hereinincorporated by reference in its entirety. Specifically, the face center220 location is found by utilizing the template method described insection 6.1.4 and FIG. 6.1 described in the USGA document mentionedabove.

A coordinate system for measuring CG location is located at the facecenter 220. In one embodiment, the positive x-axis 222 is projectingtoward the heel side of the club head, the positive z-axis 250 isprojecting toward the crown side of the club head, and the positivey-axis 216 is projecting toward the rear of the club head parallel to aground plane.

In some embodiments, the golf club head can have a CG with a CG x-axiscoordinate between about −5 mm and about 10 mm, a CG y-axis coordinatebetween about 15 mm and about 50 mm, and a CG z-axis coordinate betweenabout −10 mm and about 5 mm. In yet another embodiment, the CG y-axiscoordinate is between about 20 mm and about 50 mm.

Scorelines 224 are located on the striking face 206. In one exemplaryembodiment, a projected CG location 226 is shown on the striking faceand is considered the “sweet spot” of the club head. The projected CGlocation 226 is found by balancing the clubhead on a point. Theprojected CG location 226 is generally projected along a line that isperpendicular to the face of the club head. In some embodiments, theprojected CG location 226 is less than 2 mm above the center facelocation, less than 1 mm above the center face, or up to 1 mm or 2 mmbelow the center face location 220.

FIG. 2b illustrates a sole view of the club head showing the backportion 230 and an edge 236 between the crown 218 and sole 208 portions.In one embodiment, the club is provided with a weight port 234 and anadjustable weight 232 located in the weight port 234. In addition, aflexible recessed channel portion 240 having a channel sidewall 242 isprovided in the front half of the club head sole portion 208 proximateto the striking face 206. Within the channel portion 240, a fasteneropening 238 is provided to allow the insertion of a fastening member268, such as a screw, for engaging with the hosel insert 212 forattaching a shaft to the club head and to allow for an adjustable loft,lie, and/or face angle. In one embodiment, the hosel insert 212 isconfigured to allow for the adjustment of at least one of a loft, lie orface angle.

FIG. 2c illustrates a cross-sectional view taken along lines 2 c-2 c inFIG. 2b . In one embodiment, a machined face insert 252 is welded to afront opening on the club head. The face insert 252 has a variable facethickness having an inverted recess in the center portion of the backsurface of the face insert 252. In addition, a composite crown 254 isbonded to the crown portion 218 and rests on a bonding ledge 256. In oneembodiment, the bonding ledge is between 1-7 mm, 1-5 mm, or 1-3 mm andcontinuously extends around a circumference of the opening to supportthe crown. A plurality of ribs 258 are connected to the interior portionof the channel 240 to improve the sound of the club upon impact with agolf ball.

FIG. 2d illustrates a top view of the golf club head in the addressposition. A hosel plane 246 is shown being perpendicular to the groundplane and containing the hosel axis 214. In addition, a center facenominal face angle 244 is shown which can be adjusted by the hoselinsert 212. A positive face angle indicates the golf club face ispointed to the right of a center line target at a given measured point.A negative face angle indicates the golf club face is pointed to theleft of a centerline target at a given measured point. A topline 280 isalso shown. The topline 280 is defined as the intersection of the crownand the face of the golf club head. Often the paint line of the crownstops at the topline 280.

FIG. 2d also shows golf club head moments of inertia defined about threeaxes extending through the golf club head CG 266 including: a CG z-axis264 (see FIG. 2e ) extending through the CG 266 in a generally verticaldirection relative to the ground 202 when the club head is at addressposition, a CG x-axis 260 extending through the CG 266 in a heel-to-toedirection generally parallel to the striking surface 206 and generallyperpendicular to the CG z-axis 264, and a CG y-axis 262 extendingthrough the CG 266 in a front-to-back direction and generallyperpendicular to the CG x-axis 260 and the CG z-axis 264. The CG x-axis260 and the CG y-axis 262 both extend in a generally horizontaldirection relative to the ground 202 when the club head 200 is at theaddress position.

The moment of inertia about the golf club head CG x-axis 260 iscalculated by the following equation:

I _(CG) _(x) =∫(y ² +z ²)dm

In the above equation, y is the distance from a golf club head CGxz-plane to an infinitesimal mass dm and z is the distance from a golfclub head CG xy-plane to the infinitesimal mass dm. The golf club headCG xz-plane is a plane defined by the CG x-axis 260 and the CG z-axis264. The CG xy-plane is a plane defined by the CG x-axis 260 and the CGy-axis 262.

Moreover, a moment of inertia about the golf club head CG z-axis 264 iscalculated by the following equation:

I _(CG) _(z) =∫(x ² +y ²)dm

In the equation above, x is the distance from a golf club head CGyz-plane to an infinitesimal mass dm and y is the distance from the golfclub head CG xz-plane to the infinitesimal mass dm. The golf club headCG yz-plane is a plane defined by the CG y-axis 262 and the CG z-axis264.

In certain implementations, the club head can have a moment of inertiaabout the CG z-axis, between about 450 kg·mm2 and about 650 kg·mm2, anda moment of inertia about the CG x-axis between about 300 kg·mm2 andabout 500 kg·mm2, and a moment of inertia about the CG y-axis betweenabout 300 kg·mm2 and about 500 kg·mm2.

FIG. 2e shows the heel side view of the club head and provides a sideview of the positive y-axis 216 and how the CG 266 is projected onto theface at a projected CG location 226 previously described. A nominalcenter face loft angle 282 is shown to be the angle created by aperpendicular center face vector 284 relative to a horizontal planeparallel to a ground plane.

FIG. 2f illustrates a cross-sectional view taken along lines 2 f-2 fshown in FIG. 2d . The mechanical fastener 268 is more easily seen beinginserted into the opening 238 for threadably engaging with the sleeve212. The sleeve includes a sleeve bore 272 for allowing the shaft to beinserted for adhesive bonding with the sleeve 212. A plurality of crownribs 270 are also shown in the face to crown transition portion.

FIG. 3 illustrates the sleeve 212 and mechanical fastener 268 whenremoved from the golf club head. The embodiments described above includean adjustable loft, lie, or face angle system that is capable ofadjusting the loft, lie, or face angle either in combination with oneanother or independently from one another. For example, a portion of thesleeve 212, the sleeve bore 272, and the shaft collectively define alongitudinal axis 274 of the assembly. In one embodiment, thelongitudinal axis 274 of the assembly is co-axial with the sleeve bore272. A portion of the hosel sleeve is effective to support the shaftalong the longitudinal axis 274 of the assembly, which is offset from alongitudinal axis 214 of the interior hosel tube bore 278 by offsetangle 276. The longitudinal axis 214 is co-axial with the interior hoseltube bore 278. The sleeve can provide a single offset angle that can bebetween 0 degrees and 4 degrees, in 0.25 degree increments. For example,the offset angle can be 1.0 degree, 1.25 degrees, 1.5 degrees, 1.75degrees, 2.0 degrees, 2.25 degrees, 2.5 degrees, 2.75 degrees, or 3.0degrees. The offset angle of the embodiment shown in FIG. 2f is 1.5degrees.

FIG. 4a illustrates a plurality of vertical planes 402,404,406 andhorizontal planes 408,410,412. More specifically, the toe side verticalplane 402, center vertical plane 404 (passing through center face), andheel vertical plane 406 are separated by a distance of 30 mm as measuredfrom the center face location 414. The upper horizontal plane 408, thecenter horizontal plane 410 (passing through center face 414), and thelower horizontal plane 412 are spaced from each other by 15 mm asmeasured from the center face location 414.

FIG. 4b illustrates all three striking face surface roll contours A,B,Cthat are overlaid on top of one another as viewed from the heel side ofthe golf club. The three face surface contours are defined as facecontours that intersect the three vertical planes 402,404, 406.Specifically, toe side contour A, represented by a dashed line, isdefined by the intersection of the striking face surface and verticalplane 402 located on the toe side of the striking face. Center facevertical contour B, represented by a solid line, is defined by theintersection of the striking face surface and center face vertical plane404 located at the center of the striking face. Heel side contour C,represented by a finely dashed line, is defined by the intersection ofthe striking face surface a vertical plane 406 located on the heel sideof the striking face. Roll contours A,B,C are considered three differentroll contours across the striking face taken at three differentlocations to show the variability of roll across the face. The toe sidevertical contour A is more lofted (having positive LA° Δ) relative tothe center face vertical contour B. The heel side vertical contour C isless lofted (having a negative LA° Δ) relative to the center facevertical contour B.

FIG. 4b shows a loft angle change 434 that is measured between a centerface vector 416 located at the center face 414 and the toe side rollcurvature A having a face angle vector 432. The vertical pin distance of12.7 mm is measured along the toe side roll curvature A from a centerlocation to a crown side and a sole side to locate a crown sidemeasurement 430 point and sole side measurement points 428. A segmentline 436 connects the two points of measurement. A loft angle vector 432is perpendicular to the segment line 436. The loft angle vector 432creates a loft angle 434 with the center face vector 416 located at thecenter face point 414. As described, a more lofted angle indicates thatthe loft angle change (LA° Δ) is positive relative to the center facevector 416 and points above or higher relative to the center face vector416 as is the case for the roll curvature A.

FIG. 4c further illustrates three striking face surface bulge contoursD,E,F that are overlaid on top of one another as viewed from the crownside of the golf club. The three face surface contours are defined asface contours that intersect the three horizontal planes 408,410, 412.Specifically, crown side contour D, represented by a dashed line, isdefined by the intersection of the striking face surface and upperhorizontal plane 408 located on the upper side of the striking facetoward the crown portion. Center face contour E, represented by a solidline, is defined by the intersection of the striking face surface andhorizontal plane 408 located at the center of the striking face. Soleside contour F, represented by a finely dashed line, is defined by theintersection of the striking face surface a horizontal plane 412 locatedon the lower side of the striking face. Bulge contours D, E, F areconsidered three different bulge contours across the striking face takenat three different locations to show the variability of bulge across theface. The crown side bulge contour D is more open (having a positive FA°Δ, defined below) when compared to the center face bulge contour E. Thesole side bulge contour F is more closed (having a negative FA° Δ whenmeasured about the center vertical plane).

With the type of “twisted” bulge and roll contour defined above, a ballthat is struck in the upper portion of the face will be influenced byhorizontal contour D. A typical shot having an impact in the upperportion of a club face will influence the golf ball to land left of theintended target. However, when a ball impacts the “twisted” face contourdescribed above, horizontal contour D provides a general curvature thatpoints to the right to counter the left tendency of a typical upper faceshot.

Likewise, a typical shot having an impact location on the lower portionof the club face will land typically land to the right of the intendedtarget. However, when a ball impacts the “twisted” face contourdescribed above, horizontal contour F provides a general curvature thatpoints to the left to counter the right tendency of a typical lower faceshot. It is understood that the contours illustrated in FIGS. 4b and 4care severely distorted in order for explanation purposes.

In order to determine whether a 2-D contour, such as A, B, C, D, E, orF, is pointing left, right, up, or down, two measurement points alongthe contour can be located 18.25 mm from a center location or 36.5 mmfrom each other. A first imaginary line can be drawn between the twomeasurement points. Finally, a second imaginary line perpendicular tothe first imaginary line can be drawn. The angle between the secondimaginary line of a contour relative to a line perpendicular to thecenter face location provides an indication of how open or closed acontour is relative to a center face contour. Of course, the abovemethod can be implemented in measuring the direction of a localizedcurvature provided in a CAD software platform in a 3D or 2D model,having a similar outcome. Alternatively, the striking surface of anactual golf club can be laser scanned or profiled to retrieve the 2D or3D contour before implementing the above measurement method. Examples oflaser scanning devices that may be used are the GOM Atos Core 185 or theFaro Edge Scan Arm HD. In the event that the laser scanning or CADmethods are not available or unreliable, the face angle and the loft ofa specific point can be measured using a “black gauge” made by GolfInstruments Co. located in Oceanside, Calif. An example of the type ofgauge that can be used is the M-310 or the digital-manual combinationC-510 which provides a block with four pins for centering about adesired measurement point. The horizontal distance between pins is 36.5mm while the vertical distance between the pins is 12.7 mm.

When an operator is measuring a golf club with a black gauge for loft ata desired measurement point, two vertical pins (out of the four) areused to measure the loft about the desired point that is equidistantbetween the two vertical pins that locate two vertical points. Whenmeasuring a golf club with a black gauge for face angle at a desiredmeasurement point, two horizontal pins (out of the four) are used tomeasure the face angle about the desired point. The desired point isequidistant between the two horizontal points located by the pins whenmeasuring face angle.

FIG. 4c shows a face angle 420 that is measured between a center facevector 416 located at the center face 414 and the crown side bulgecurvature D having a face angle vector 418. The horizontal pin distanceof 18.25 mm is measured along the crown side bulge curvature D from acenter location to a heel side and a toe side to locate a heel sidemeasurement 426 point and toe side measurement points 424. A segmentline 422 connects the two points of measurement. A face angle vector 418is perpendicular to the segment line 422. The face angle vector 418creates a face angle 420 with the center face vector 416 located at thecenter face point 414. As described, an open face angle indicates thatthe face angle change (FA° Δ) is positive relative to the center facevector 416 and points to the right as is the case for the bulgecurvature D.

FIG. 5 shows a desired measurement point Q0 located at the center of thestriking face 500. A horizontal plane 522 and a vertical plane 502intersect at the desired measurement point Q0 and divide the strikingface 500 into four quadrants. The upper toe quadrant 514, the upper heelquadrant 518, the lower heel quadrant 520, and the lower toe quadrant516 all form the striking face 500, collectively. In one embodiment, theupper toe quadrant 514 is more “open” than all the other quadrants. Inother words, the upper toe quadrant 514 has a face angle pointing to theright, in the aggregate. In other words, if a plurality of evenly spacedpoints (for example a grid with measurement points being spaced from oneanother by 5 mm) covering the entire upper toe quadrant 514 weremeasured, it would have an average face angle that points right of theintended target more than any other quadrant.

The term “open” is defined as having a face angle generally pointing tothe right of an intended target at address, while the term “closed” isdefined as having a face angle generally pointing to the left of anintended target ad address. In one embodiment, the lower heel quadrant520 is more “closed” than all the other quadrants, meaning it has a faceangle, in the aggregate, that is pointing more left than any of theother quadrants.

If the edge of the striking surface 500 is not visually clear, the edgeof the striking face 500 is defined as a point at which the strikingsurface radius becomes less than 127 mm. If the radius is not easilycomputed within a computer modeling program, three points that are 0.1mm apart can be used as the three points used for determining thestriking surface radius. A series of points will define the outerperimeter of the striking face 500. Alternatively, if a radius is noteasily obtainable in a computer model, a 127 mm curvature gauge can beused to detect the edge of the face of an actual golf club head. Thecurvature gauge would be rotated about a center face point to determinethe face edge.

In one illustrative example in FIG. 5, the face angle and loft aremeasured for a center face point Q0 when an easily measureable computermodel method is not available, for example, when an actual golf clubhead is measured. A black gauge is utilized to measure the face angle byselecting two horizontal points 506,508 along the horizontal plane 522that are 36.5 mm apart and centered about the center face point Q0 sothat the horizontal points 506,508 are equidistant from the center facepoint Q0. The two pins from the black gauge engage these two points andprovide a face angle measurement reading on the angle measurementreadout provided. Furthermore, a loft is measured about the Q0 point byselecting two vertical points 512,510 that are spaced by a verticaldistance of 12.7 mm apart from each other. The two vertical pins fromthe black gauge engage these two vertical points 512,510 and provide aloft angle measurement reading on the readout provided.

The positive x-axis 522 for face point measurements extends from thecenter face toward the heel side and is tangent to the center face. Thepositive y-axis 502 for face point measurements extends from the centerface toward the crown of the club head and is tangent to the centerface. The x-y coordinate system at center face, without a loftcomponent, is utilized to locate the plurality of points P0-P36 andQ0-Q8, as described below. The positive z-axis 504 extends from the facecenter and is perpendicular to the face center point and away from theinternal volume of the club head. The positive z-axis 504 and positivey-axis 502 will be utilized as a reference axis when the face angle andloft angle are measured at another x-y coordinate location, other thancenter face.

FIG. 5 further shows two critical points Q3 and Q6 located atcoordinates (0 mm, 15 mm) and (0 mm, −15 mm), respectively. As usedherein, the terms “1° twist” and “2° twist” are defined as the totalface angle change between these two critical point locations at Q3 andQ6. For example, a “1° twist” would indicate that the Q3 point has a0.5° twist relative to the center face, Q0, and the Q6 point has a −0.5°twist relative to the center face, Q0. Therefore, the total degree oftwist as an absolute value between the critical points Q3,Q6 is 1°,hence the nomenclature “1° twist”.

To further the understanding of what is meant by a “twisted face”, FIG.6a provides an isometric view of an over-exaggerated twisted strikingsurface plane 614 of “10° twist” to illustrate the concept as applied toa golf club striking face. Each point located on the golf club face hasan associated loft angle change (defined as “LA° Δ”) and face anglechange (defined as “FA° 4”). Each point has an associated loft anglechange (defined as “LA° Δ”) and face angle change (defined as “FA° 4”).

FIG. 6a shows the center face point, Q0, and the two critical pointsQ3,Q6 described above, and a positive x-axis 600, positive z-axis 604,and positive y-axis 602 located on a twisted plane in an isometric view.The center face has a perpendicular axis 604 that passes through thecenter face point Q0 and is perpendicular to the twisted plane 614.Likewise, the critical points Q3 and Q6 also have a reference axis 610,612 which is parallel to the center face perpendicular axis 604. Thereference axes 610, 612 are utilized to measure a relative face anglechange and loft angle change at these critical point locations. Thecritical points Q3, Q6 each have a perpendicular axis 608, 606 that isperpendicular to the face. Thus, the face angle change is defined at thecritical points as the change in face angle between the reference axis610,612 and the relative perpendicular axis 608, 606.

FIG. 6b shows a top view of the twisted plane 614 and furtherillustrates how the face angle change is measured between theperpendicular axes 608, 606 at the critical points and the referenceaxes 610, 612 that are parallel with the center face perpendicular axis604. A positive face angle change +FA° Δ indicates a perpendicular axisat a measured point that points to the right of the relative referenceaxis. A negative face angle change −FA° Δ indicates a perpendicular axisthat points to the left of the relative reference axis. The face anglechange is measured within the plane created by the positive x-axis 600and positive z-axis 604.

FIG. 6c shows a heel side view of a twisted plane 614 and the loft anglechange between the perpendicular axes 608,606 and the reference axes610,612 at the critical point locations. A positive loft angle change+LA° Δ indicates a perpendicular axis at a measured point that pointsabove the relative reference axis. A negative loft angle change −LA° Δindicates a perpendicular axis that points below the relative referenceaxis. The loft angle is measured within the plane created by thepositive z-axis 604 and positive y-axis 602 for a given measured point.

FIG. 7 shows an additional plurality of points Q0-Q8 that are spacedapart across the striking face in a grid pattern. In addition to thecritical points Q3,Q6 described above, heel side points Q5,Q2,Q8 arespaced 30 mm away from a vertical axis 700 passing through the centerface. Toe side points Q4,Q1,Q7 are spaced 30 mm away from the verticalaxis 700 passing through the center face. Crown side points Q3,Q4,Q5 arespaced 15 mm away from a horizontal axis 702 passing through the centerface. Sole side points Q6,Q7,Q8 are spaced 15 mm away from thehorizontal axis 702. Point Q5 is located in an upper heel quadrant at acoordinate location (30 mm, 15 mm) while point Q7 is located in a lowertoe quadrant at a coordinate location (−30 mm, −15 mm). Point Q4 islocated in an upper toe quadrant at a coordinate location (−30 mm, 15mm) while point Q8 is located in a lower heel quadrant at a coordinatelocation (30 mm, −15 mm).

It is understood that many degrees of twist are contemplated and theembodiments described are not limiting. For example, a golf club havinga “0.25° twist”, “0.75° twist”, “1.25° twist”, “1.5° twist”, “1.75°twist”, “2.25° twist”, “2.5° twist”, “2.75° twist, “3° twist”, “3.25°twist”, “3.5° twist”, “3.75° twist”, “4.25° twist”, “4.5° twist”, “4.75°twist”, “5° twist”, “5.25° twist”, “5.5° twist”, “5.75° twist”, “6°twist”, “6.25° twist”, “6.5° twist”, “6.75° twist”, “7° twist”, “7.25°twist”, “7.5° twist”, “7.75° twist”, “8° twist”, “8.25° twist”, “8.5°twist”, “8.75° twist”, “9° twist”, “9.25° twist”, “9.5° twist”, “9.75°twist”, and “10° twist” are considered other possible embodiments of thepresent invention. A golf club having a degree of twist greater than 0°,between 0.25° and 5°, between 0.1° and 5°, between 0° and 5°, between 0°and 10°, or between 0° and 20° are contemplated herein.

Utilizing the grid pattern of FIG. 7, a plurality of embodiments havinga nominal center face loft angle of 9.5°, a bulge of 330.2 mm, and aroll of 279.4 mm were analyzed having a “0.5° twist”, “1° twist”, “2°twist”, and “4° twist”. A comparison club having “0° twist” is providedfor reference in contrast to the embodiments described.

Table 1 shows the LA° Δ and FA° Δ relative to center face for pointslocated along the vertical axis 700 and horizontal axis 702 (for examplepoints Q1, Q2, Q3, and Q6). With regard to points located away from thevertical axis 700 and horizontal axis 702, the LA° Δ and FA° Δ aremeasured relative to a corresponding point located on the vertical axis700 and horizontal axis 702, respectively.

For example, regarding point Q4, located in the upper toe quadrant ofthe golf club head at a coordinate of (−30 mm, 15 mm), the LA° Δ ismeasured relative to point Q3 having the same vertical axis 700coordinate at (0 mm, 15 mm). In other words, both Q3 and Q4 have thesame y-coordinate location of 15 mm. Referring to Table 1, the LA° Δ ofpoint Q4 is 0.4° with respect to the loft angle at point Q3. The LA° Δof point Q4 is measured with respect to point Q3 which is located in acorresponding upper toe horizontal band 704.

In addition, regarding point Q4, located in the upper toe quadrant ofthe golf club head at a coordinate of (−30 mm, 15 mm), the FA° Δ ismeasured relative to point Q1 having the same horizontal axis 702coordinate at (−30 mm, 0 mm). In other words, both Q1 and Q4 have thesame x-coordinate location of −30 mm. Referring to Table 1, the FA° Δ ofpoint Q4 is 0.2° with respect to the face angle at point Q1. The FA° Δof point Q4 is measured with respect to point Q1 which is located in acorresponding upper toe vertical band 706.

To further illustrate how LA° Δ and FA° Δ are calculated for pointslocated within a quadrant that are away from a vertical or horizontalaxis, the LA° Δ of point Q8 is measured relative to a loft angle locatedat point Q6 within a lower heel quadrant horizontal band 708. Likewise,the FA° Δ of point Q8 is measured relative to a face angle located atpoint Q2 within a lower heel quadrant vertical band 710.

In summary, the LA° Δ and FA° Δ for all points that are located alongeither a horizontal 702 or vertical axis 700 are measured relative tocenter face Q0. For points located within a quadrant (such as points Q4,Q5, Q7, and Q8) the LA° Δ is measured with respect to a correspondingpoint located in a corresponding horizontal band, and the FA° Δ of agiven point is measured with respect to a corresponding point located ina corresponding vertical band. In FIG. 7, not all bands are shown in thedrawing for the improved clarity of the drawing.

The reason that points located within a quadrant have a differentprocedure for measuring LA° Δ and FA° Δ is that this method eliminatesany influence of the bulge and roll curvature on the LA° Δ and FA° Δnumbers within a quadrant. Otherwise, if a point located within aquadrant is measured with respect to center face, the LA° Δ and FA° Δnumbers will be dependent on the bulge and roll curvature. Thereoreutilizing the horizontal and vertical band method of measuring LA° Δ andFA° Δ within a quadrant eliminates any undue influence of a specificbulge and roll curvature. Thus the LA° Δ and FA° Δ numbers within aquadrant should be applicable across any range of bulge and rollcurvatures in any given head. The above described method of measuringLA° Δ and FA° Δ within a quadrant has been applied to all examplesherein.

The relative LA° Δ and FA° Δ can be applied to any lofted driver, suchas a 9.5°, 10.5°, 12° lofted clubs or other commonly used loft anglessuch as for drivers, fairway woods, hybrids, irons, or putters.

TABLE 1 Relative to Center Face and Bands Example 1 Example 2 Example 3Example 4 X-axis Y-Axis 0.5° twist 1° twist 2° twist 4° twist 0° twistPoint (mm) (mm) LA° Δ FA° Δ LA° Δ FA° Δ LA° Δ FA° Δ LA° Δ FA° Δ LA° ΔFA° Δ Q0 0 0 0 0 0 0 0 0 0 0 0 0 Q1 −30 0 0.5 5.7 1 5.7 2 5.6 4 5.6 05.7 Q2 30 0 −0.5 −5.7 −1 −5.7 −2 −5.6 −4 −5.6 0 −5.7 Q3 0 15 3.4 0.253.4 0.5 3.4 1 3.4 2 3.4 0 Q4 −30 15 0.4 0.2 0.9 0.4 1.9 1 3.9 2 0 0 Q530 15 −0.5 0.3 −1 0.5 −2 0.9 −4 1.9 0 0 Q6 0 −15 −3.4 −0.25 −3.4 −0.5−3.4 −1 −3.4 −2 −3.4 0 Q7 −30 −15 0.5 −0.3 1 −0.5 2 −0.9 4 −2 0 0 Q8 30−15 −0.5 −0.2 −1 −0.4 −2 −1 −4.1 −2 0 0

In Examples 1-4 of Table 1, the critical point Q3 has a LA° Δ of +3.4°with respect to the center face. In some embodiments, a LA° Δ at Q3 isbetween 0° and 7°, between 1° and 5°, between 2° and 4°, or between 3°and 4°. A FA° Δ of greater than zero at the critical point Q3 (15 mmabove the center face) is shown. The FA° Δ at the critical point Q3 canbe between 0° and 5°, between 0.1° and 4°, between 0.2° and 4°, orbetween 0.2° and 3°, in some embodiment. In addition, the critical pointQ6 has a LA° Δ of −3.4°, or less than zero, with respect to the centerface for Examples 1-4. In some embodiments, a LA° Δ at Q6 is between 0°and −7°, between −1° and −5°, between −2° and −4°, or between −3° and−4°. A FA° Δ of less than zero at the critical point Q6 (−15 mm belowthe center face) is shown. In some embodiments, the FA° Δ at thecritical point Q6 can be between 0° and −5°, between −0.1° and −4°,between −0.2° and −4°, or between −0.2° and −3°. In Examples 1-4, theloft angle remains constant relative to center face at the criticalpoints Q3,Q6 while the face angle changes relative to center face as thedegree of twist is changed.

Examples 1-4 of Table 1 further show a heel side point Q2 located at ax-y coordinate (30 mm, 0 mm) where the LA° Δ relative to center is−0.5°, −1°, −2°, and −4°, respectively, for each example. Therefore, aLA° Δ of less than zero at the point Q2 is shown. In some embodiments,the LA° Δ at the Q2 point is between 0° and −8°. In addition, Examples1-4 at Q2 show a FA° Δ of less than −4° relative to center face as thedegree of twist gets larger. In some embodiments, the FA° Δ at Q2 isbetween −0.2° and −10°, between −0.3° and −9°, or between −1° and −8°.

Examples 1-4 of Table 1 further show a toe side point Q1 located at acoordinate (−30 mm, 0 mm) where the LA° Δ relative to center is 0.5°,1°, 2°, and 4°, respectively. Therefore, a LA° Δ of greater than zero atthe point Q1 is shown. In some embodiments, the LA° Δ at the Q1 point isbetween 0° and 8°, between 0.1° and 7°, between 0.2° and 6°, or between0.3° and 5°. In addition, a FA° Δ at Q1 can be between between 1° and8°, between 2° and 7°, or between 3° and 6°.

Examples 1-4 of Table 1 further show at least one upper heel quadrantpoint Q5 having a FA° Δ relative to point Q2 that is greater than 0.1°,greater than 0.2° or 0.3°. For instance, at point Q5, Examples 1, 2, 3,and 4 show a FA° Δ relative to point Q2 of 0.3°, 0.5°, 0.9°, and 1.9°,respectively, which are all greater than 0.1°. Examples 1-4 of Table 1also show at least one upper heel quadrant point Q5 having a LA° Δrelative to point Q3 that is less than −0.2°. For instance, at point Q5,Examples 1, 2, 3, and 4 show a LA° Δ relative to point Q3 of −0.5°, −1°,−2°, and −4°, respectively, which are all less than −0.1°, less than−0.3, or less than −0.4.

Examples 1-4 of Table 1 further show at least one upper toe quadrantpoint Q4 having a FA° Δ relative to point Q1 that is greater than 0.1°.For instance, at point Q5, Examples 1, 2, 3, and 4 show a FA° Δ relativeto point Q1 of 0.2°, 0.4°, 1°, and 2°, respectively, which are allgreater than 0.15°. Examples 1-4 of Table 1 also show at least one uppertoe quadrant point Q4 having a LA° Δ relative to point Q1 that isgreater than 0.1°. For instance, at point Q4, Examples 1, 2, 3, and 4show a LA° Δ relative to point Q1 of 0.4°, 0.9°, 1.9°, and 3.9°,respectively, which are all greater than 0.2° or greater than 0.3°.

Examples 1-4 of Table 1 further show at least one lower heel quadrantpoint Q8 having a FA° Δ relative to point Q2 that is less than −5.7°.For instance, at point Q8, Examples 1, 2, 3, and 4 show a FA° Δ relativeto point Q2 of −0.2°, −0.4°, −1°, and −2°, respectively, which are allless than −0.1°. Examples 1-4 of Table 1 also show at least one lowerheel quadrant point Q8 having a LA° Δ relative to point Q6 that is lessthan −0.1°. For instance, at point Q8, Examples 1, 2, 3, and 4 show aLA° Δ relative to point Q6 of −0.5°, −1°, −2°, and −4.1°, respectively,which are all less than −0.2°, less than 0.3° or less than 0.4°.

Examples 1-4 of Table 1 further show at least one lower toe quadrantpoint Q7 having a FA° Δ relative to point Q1 that is less than −0.1°.For instance, at point Q7, Examples 1, 2, 3, and 4 show a FA° Δ relativeto center of −0.3°, −0.5°, −0.9°, and −2°, respectively, which are allless than −0.2°. Examples 1-4 of Table 1 also show at least one lowerheel quadrant point Q7 having a LA° Δ relative to point Q6 that isgreater than 0.2°. For instance, at point Q7, Examples 1, 2, 3, and 4show a LA° Δ relative to point Q6 of 0.5°, 1°, 2°, and 4°, respectively,which are all greater than 0.3° or greater than 0.4°.

Table 2 shows the same embodiments of Table 1 but provides thedifference in LA° Δ and FA° Δ when compared to the golf club head with“0° twist” as the base comparison. Example 1 has up to +/−0.5° of LA° Δand up to +/−0.3 FA° Δ when compared to the golf club head with “0°twist”. Example 2 has up to +/−1° of LA° Δ and up to +/−0.5 FA° Δ whencompared to the golf club head with “0° twist”. Example 3 has up to+/−2° of LA° Δ and up to +/−1 FA° Δ when compared to the golf club headwith “0° twist”. Example 4 has up to +/−4.1° of LA° Δ and up to +/−2.1FA° Δ when compared to the golf club head with “0° twist”.

In Examples 1-4, the LA° Δ and FA° Δ relative to center face remainsunchanged at the center face location (0 mm, 0 mm) when compared to the“0° twist” head. However, all other points away from the center facelocation in Examples 1-4 have some non-zero amount of either LA° Δ orFA° Δ.

TABLE 2 Relative to Zero Degree Twist Example 1 Example 2 Example 3Example 4 X-axis Y-Axis 0.5° twist 1° twist 2° twist 4° twist Point (mm)(mm) LA° Δ FA° Δ LA° Δ FA° Δ LA° Δ FA° Δ LA° Δ FA° Δ Q0 0 0 0 0 0 0 0 00 0 Q1 −30 0 0.5 0 1 0 2 −0.1 4 −0.1 Q2 30 0 −0.5 0 −1 0 −2 0.1 −4 0.1Q3 0 15 0 0.25 0 0.5 0 1 0 2 Q4 −30 15 0.4 0.2 0.9 0.4 1.9 1 3.9 2 Q5 3015 −0.5 0.3 −1 0.5 −2 0.9 −4 1.9 Q6 0 −15 0 −0.25 0 −0.5 0 −1 0 −2 Q7−30 −15 0.5 −0.3 1 −0.5 2 −0.9 4 −2 Q8 30 −15 −0.5 −0.2 −1 −0.4 −2 −1−4.1 −2

FIG. 8 illustrates a plurality of points P0-P36 at which the face angleand loft angle are measured in a computer model. However, these samepoints can be measured on an actual golf club head utilizing the methodsdescribed above. Table 3 below provides the exact measurement of FA° Δand LA° Δ at the thirty-seven plurality points spread across the golfclub face. The FA° Δ and LA° Δ of each point is provided for twodifferent embodiments having a 1° twist and 2° twist and a nominalcenter face loft angle of 9.2°, a bulge of 330.2 mm, and a roll of 279.4mm are identified as Examples 5 and 6, respectively. Examples 5 and 6are provided next to a golf club face that has 0° of twist forcomparison purposes.

TABLE 3 Relative to Center Face and Bands Example 5 Example 6 X-axisY-axis 1° twist 2° twist 0° twist Point (mm) (mm) LA° Δ FA° Δ LA° Δ FA°Δ LA° Δ FA° Δ P0 0 0 0.000 0.000 0.000 0.000 0.000 0.000 P1 0 5 1.0250.167 1.025 0.333 1.025 0.000 P6 0 −5 −1.025 −0.167 −1.025 −0.333 −1.0250.000 P2 0 10 2.051 0.333 2.051 0.667 2.051 0.000 P7 0 −10 −2.051 −0.333−2.051 −0.667 −2.051 0.000 P3 0 12 2.462 0.400 2.462 0.800 2.462 0.000P8 0 −12 −2.462 −0.400 −2.462 −0.800 −2.462 0.000 P4 0 15 3.077 0.5003.077 1.000 3.077 0.000 P9 0 −15 −3.077 −0.500 −3.077 −1.000 −3.0770.000 P5 0 20 4.105 0.667 4.105 1.333 4.105 0.000 P10 0 −20 −4.105−0.667 −4.105 −1.333 −4.105 0.000 P11 5 0 −0.167 −0.868 −0.333 −0.8680.000 −0.868 P16 −5 0 0.167 0.868 0.333 0.868 0.000 0.868 P12 10 0−0.333 −1.735 −0.667 −1.735 0.000 −1.735 P17 −10 0 0.333 1.735 0.6671.735 0.000 1.735 P13 18 0 −0.600 −3.125 −1.200 −3.125 0.000 −3.125 P18−18 0 0.600 3.125 1.200 3.125 0.000 3.125 P14 25 0 −0.833 −4.342 −1.667−4.342 0.000 −4.342 P19 −25 0 0.833 4.342 1.667 4.342 0.000 4.342 P15 300 −1.000 −5.213 −2.000 −5.213 0.000 −5.213 P20 −30 0 1.000 5.213 2.0005.213 0.000 5.213 P33 10 10 −0.333 0.333 −0.667 0.667 0.000 0.000 P34 1812 −0.600 0.400 −1.200 0.800 0.000 0.000 P35 25 20 −0.833 0.667 −1.6671.333 0.000 0.000 P36 30 15 −1.000 0.500 −2.000 1.000 0.000 0.000 P21−10 10 0.333 0.333 0.667 0.667 0.000 0.000 P22 −18 12 0.600 0.400 1.2000.800 0.000 0.000 P23 −25 20 0.833 0.667 1.667 1.333 0.000 0.000 P24 −3015 1.000 0.500 2.000 1.000 0.000 0.000 P29 10 −10 −0.333 −0.333 −0.667−0.667 0.000 0.000 P30 18 −12 −0.600 −0.400 −1.200 −0.800 0.000 0.000P31 25 −20 −0.833 −0.667 −1.667 −1.333 0.000 0.000 P32 30 −15 −1.000−0.500 −2.000 −1.000 0.000 0.000 P25 −10 −10 0.333 −0.333 0.667 −0.6670.000 0.000 P26 −18 −12 0.600 −0.400 1.200 −0.800 0.000 0.000 P28 −25−20 0.833 −0.667 1.667 −1.333 0.000 0.000 P27 −30 −15 1.000 −0.500 2.000−1.000 0.000 0.000

Table 3 shows the same nine key points of measurement shown in Table 1.Specifically, points P0, P4, P9, P15, P20, P24, P27, P32, and P36correspond to the locations of points Q0-Q8 in Table 1. However,additional points have been measured to provide a higher resolution ofthe twisted face in Examples 5 and 6.

Point P5 located at x-y coordinate (0 mm, 20 mm) and point P10 locatedat x-y coordinate (0 mm, −20 mm) are helpful in determining the extremeface angle changes further away from the center face. In Example 5 ofTable 3 at point P5, the FA° Δ is between 0.1° and 4°, between 0.2° and3.5°, between 0.3° and 3°, between 0.4° and 3°, or between 0.5° and 2°.The LA° Δ at point P5 is between 1° and 10°, between 2° and 8°, between3° and 7°, or between 3° and 6°.

In Example 5 of Table 3 at point P10, the FA° Δ is between −0.1° and−4°, between −0.2° and −3.5°, between −0.3° and −3°, between −0.4° and−3°, or between −0.5° and −2°. The LA° Δ at point P10 is between −1° and−10°, between −2° and −8°, between −3° and −7°, or between −3° and −6°.

Table 3 and FIG. 8 also show a plurality of points located in eachquadrant. The upper toe quadrant has at least four measured points P21,P22, P23, P24. The lower toe quadrant has at least four measured pointsP25, P26, P27, P28. The upper heel quadrant has at least four measuredpoints P33, P34, P35, P36. The lower heel quadrant has at least fourmeasured points P29, P30, P31, P32.

The average of the FA° Δ and LA° Δ of the four points described in eachquadrant are shown in Table 4 below.

TABLE 4 Average in Quadrants Example 5 Example 6 1° twist 2° twist 0°twist Avg. Avg. Avg. Avg. Avg. Avg. LA° Δ FA° Δ LA° Δ FA° Δ LA° Δ FA° ΔUpper Toe 0.692 0.475 1.383 0.950 0.000 0.000 Quadrant Upper Heel −0.6920.475 −1.383 0.950 0.000 0.000 Quadrant Lower Toe 0.692 −0.475 1.383−0.950 0.000 0.000 Quadrant Lower Heel −0.692 −0.475 −1.383 −0.950 0.0000.000 Quadrant

Table 4 shows that average FA° Δ in Example 5 for the upper toe quadrantand the upper heel quadrant are more open (more positive) than the 0°twist golf club head by more than 0.1°, more than 0.2°, more than 0.3°,or more than 0.4°. In some embodiments the upper toe quadrant and upperheel quadrant have an average FA° Δ more open than the 0° twist golfclub by between 0.1° to 0.8°, 0.2° to 0.6°, or 0.3° to 0.5° more open.The lower toe quadrant and lower heel quadrant of Example 5 has a FA° Δthat is more closed (more negative) than the 0° twist golf club head. Insome embodiments, the FA° Δ relative to a 0° twist club head in thelower toe quadrant and lower heel quadrant is less than −0.1°, less than−0.2, less than −0.3, or less than −0.4. In some embodiments, the FA° Δrelative to a 0° twist club head in the lower toe quadrant and lowerheel quadrant is between −0.1° to −0.8°, −0.2° to −0.6°, or −0.3° to−0.5°.

Table 4 shows that average FA° Δ in Example 6 for the upper toe quadrantand the upper heel quadrant are more open (more positive) than the 0°twist golf club head by more than 0.6°, more than 0.7°, more than 0.8°,or more than 0.9°. In some embodiments the upper toe quadrant and upperheel quadrant are more open than the 0° twist golf club by between 0.6°to 1.2°, 0.7° to 1.1°, or 0.8° to 1° more open. The lower toe quadrantand lower heel quadrant of Example 6 has a FA° Δ that is more closed(more negative) than the 0° twist golf club head. In some embodiments,the FA° Δ relative to a 0° twist club head in the lower toe quadrant andlower heel quadrant is less than −0.6°, less than −0.7, less than −0.8,or less than −0.9. In some embodiments, the FA° Δ relative to a 0° twistclub head in the lower toe quadrant and lower heel quadrant is between−0.6° to −1.2°, −0.7° to −1.1°, or −0.8° to −1°.

Table 4 shows that average LA° Δ in Example 5 for the upper toe quadrantand lower toe quadrant are more lofted (more positive) than the 0° twistgolf club head by more than 0.2°, more than 0.3°, more than 0.4°, morethan 0.5°, or more than 0.6°. In some embodiments, the upper toequadrant and lower toe quadrant have a LA° Δ between 0.2° to 1°, between0.3° to 0.9°, between 0.4° to 0.8°, or between 0.5° to 0.7° more lofted.The average LA° Δ of the upper heel quadrant and lower heel quadrant ofExample 5 relative to a 0° twist club head are less lofted (morenegative) than the 0° twist golf club head by less than −0.2° less than−0.3°, less than −0.4°, less than −0.5°, or less than −0.6°. In someembodiments, the upper heel quadrant and lower heel quadrant have a LA°Δ between −0.2° to −1°, between −0.3° to −0.9°, between −0.4° to −0.8°,or between −0.5° to −0.7° less lofted. The lower toe quadrant and uppertoe quadrant of Example 5 are more lofted (more positive) than the 0°twist golf club head by more than 0.1° or between 0° to 1.5° morelofted. The lower heel quadrant and upper heel quadrant of Example 5 areless lofted (more negative) than the 0° twist golf club head by lessthan −0.1° or between 0° to −1° less lofted.

Table 4 shows that average LA° Δ in Example 6 for the upper toe quadrantand lower toe quadrant are more lofted (more positive) than the 0° twistgolf club head by more than 0.5°, more than 0.6°, more than 0.7°, morethan 0.8°, or more than 0.9°. In some embodiments, the upper toequadrant and lower toe quadrant have a LA° Δ between 0.5° to 2.5°,between 0.6° to 2°, between 0.7° to 1.8°, or between 0.9° to 1.5° morelofted. The average LA° Δ of the upper heel quadrant and lower heelquadrant of Example 6 is less lofted (more negative) than the 0° twistgolf club head by less than-0.5° less than −0.6°, less than −0.7°, lessthan −0.8°, or less than −0.9°. In some embodiments, the upper heelquadrant and lower heel quadrant have an average LA° Δ relative to 0°twist club head of between −0.5° to −2.5°, between −0.6° to −2°, between−0.7° to −1.8°, or between −0.9° to −1.5° less lofted. The lower toequadrant and upper toe quadrant of Example 6 are more lofted (morepositive) than the 0° twist golf club head by more than 0.1° or between0° to 2.5° more lofted. The lower heel quadrant and upper heel quadrantof Example 6 are less lofted (more negative) than the 0° twist golf clubhead by less than −0.1° or between 0° to −2.5° less lofted.

Therefore, Examples 5 and 6 show a golf club head having four quadrantswhere the FA° Δ is more open (more positive) in the upper heel and toequadrants and more closed (more negative) in the lower heel and toequadrants. Examples 5 and 6 also show a golf club head having fourquadrants where the LA° Δ is more lofted (more positive) in the uppertoe quadrant and lower toe quadrant while being less lofted (morenegative) in the upper heel quadrant and lower heel quadrant whencompared to a 0° twist golf club head.

FIG. 9 provides a chart showing the rate of change of FA° Δ relative toa y-axis 800 change with zero x-axis 802 change. In other words, FIG. 9graphs the points P0-P10 shown in Table 3 above. It is noted that thepoints P0-P10 lie along the y-axis 800 only and have no x-axis 802component. The rate of change is shown by the trend line fit to themeasurements of Examples 5 and 6. The FA° Δ for Example 5 and 6 have atrend line defined as:

y=0.0333x  (Eq. 1)Example 5

y=0.0667x  (Eq. 2)Example 6

Equation 1 illustrates that for every 1 mm in movement along the y-axis800, there is a relative FA° Δ of 0.0333° for a “1° twist” golf clubhead. Equation 2 shows that for every 1 mm in movement along the y-axis800, there is a corresponding relative FA° Δ of 0.0667° for a “2° twist”golf club head. The slope of the equation describes the rate of changeof the FA° Δ relative to the measurement point as it is moved along they-axis 800. Therefore, the rate of change can be represented as a x/mmwhere x is the FA° Δ (in units of ° Δ).

In some embodiments, the FA° Δ to y-axis rate of change is greater thanzero, greater than 0.01° Δ/mm, greater than 0.02° Δ/mm, greater than0.03° Δ/mm, greater than 0.04° Δ/mm, greater than 0.05° Δ/mm, or greaterthan 0.6° Δ/mm. In some embodiments, the FA° Δ to y-axis rate of changeis between 0.005° Δ/mm and 0.2° Δ/mm, between 0.01° Δ/mm and 0.1° Δ/mm,between 0.02° Δ/mm and 0.09° Δ/mm, or between 0.03° Δ/mm and 0.08° Δ/mm.

FIG. 10 shows a chart illustrating the rate of change of the LA° Δrelative to a x-axis 802 change with zero y-axis 800 change. In otherwords, FIG. 10 graphs the points P11-P20 shown in Table 3 above. It isnoted that the points P11-P20 lie along the x-axis 802 only and have noy-axis 800 component.

The LA° Δ for Example 5 and 6 have a trend line defined as:

y=−0.0333x  (Eq. 3)Example 5

y=−0.0667x  (Eq. 4)Example 6

Equation 3 illustrates that for every 1 mm in movement along the x-axis802, there is a relative LA° Δ of −0.0333° for a “1° twist” golf clubhead. Equation 2 shows that for every 1 mm in movement along the x-axis802, there is a corresponding relative LA° Δ of −0.0667° for a “2°twist” golf club head. The rate of change for the LA° Δ is negative forevery positive movement along the x-axis 802.

In some embodiments, the LA° Δ to x-axis rate of change is less thanzero for every millimeter, less than −0.01° Δ/mm, less than −0.02° Δ/mm,less than −0.03° Δ/mm, less than −0.04° Δ/mm, less than −0.05° Δ/mm, orless than −0.06° Δ/mm.

In some embodiments, the LA° Δ to x-axis rate of change is between−0.005° Δ/mm and −0.2° Δ/mm, between −0.01° Δ/mm and −0.1° Δ/mm, between−0.02° Δ/mm and −0.09° Δ/mm, or between −0.03° Δ/mm and −0.08° Δ/mm.

TABLE 5 Relative to Zero Degree Twist Example 5 Example 6 X-axis Y-axis1° twist 2° twist Point (mm) (mm) LA° Δ FA° Δ LA° Δ FA° Δ P0 0 0 0.0000.000 0.000 0.000 P1 0 5 0.000 0.167 0.000 0.333 P6 0 −5 0.000 −0.1670.000 −0.333 P2 0 10 0.000 0.333 0.000 0.667 P7 0 −10 0.000 −0.333 0.000−0.667 P3 0 12 0.000 0.400 0.000 0.800 P8 0 −12 0.000 −0.400 0.000−0.800 P4 0 15 0.000 0.500 0.000 1.000 P9 0 −15 0.000 −0.500 0.000−1.000 P5 0 20 0.000 0.667 0.000 1.333 P10 0 −20 0.000 −0.667 0.000−1.333 P11 5 0 −0.167 0.000 −0.333 0.000 P16 −5 0 0.167 0.000 0.3330.000 P12 10 0 −0.333 0.000 −0.667 0.000 P17 −10 0 0.333 0.000 0.6670.000 P13 18 0 −0.600 0.000 −1.200 0.000 P18 −18 0 0.600 0.000 1.2000.000 P14 25 0 −0.833 0.000 −1.667 0.000 P19 −25 0 0.833 0.000 1.6670.000 P15 30 0 −1.000 0.000 −2.000 0.000 P20 −30 0 1.000 0.000 2.0000.000 P33 10 10 −0.333 0.333 −0.667 0.667 P34 18 12 −0.600 0.400 −1.2000.800 P35 25 20 −0.833 0.667 −1.667 1.333 P36 30 15 −1.000 0.500 −2.0001.000 P21 −10 10 0.333 0.333 0.667 0.667 P22 −18 12 0.600 0.400 1.2000.800 P23 −25 20 0.833 0.667 1.667 1.333 P24 −30 15 1.000 0.500 2.0001.000 P29 10 −10 −0.333 −0.333 −0.667 −0.667 P30 18 −12 −0.600 −0.400−1.200 −0.800 P31 25 −20 −0.833 −0.667 −1.667 −1.333 P32 30 −15 −1.000−0.500 −2.000 −1.000 P25 −10 −10 0.333 −0.333 0.667 −0.667 P26 −18 −120.600 −0.400 1.200 −0.800 P28 −25 −20 0.833 −0.667 1.667 −1.333 P27 −30−15 1.000 −0.500 2.000 −1.000

Table 5 shows the same embodiments of Table 3 but provides thedifference in LA° Δ and FA° Δ when compared to the golf club head with“0° twist” as the base comparison. Example 5 has up to about +/−1° ofLA° Δ or up to about +/−0.7 FA° Δ when compared to the golf club headwith “0° twist”. Example 6 has up to about +/−2° of LA° Δ and up to+/−1.4 FA° Δ when compared to the golf club head with “0° twist”.

In Examples 5 and 6, the LA° Δ and FA° Δ relative to center face remainsunchanged at the center face location (0 mm, 0 mm) when compared to the“0° twist” head. However, all other points away from the center facelocation in Examples 5 and 6 also have some non-zero amount of change ineither LA° Δ or FA° Δ.

The numbers provided in the Tables above show loft angle change or faceangle change relative to center face location or relative to a key pointwithin a band. However, the actual nominal face angle or loft angle canbe calculated quantitatively for a desired point using the belowequation:

$\begin{matrix}{{LA} = {{CFLA} + {\arcsin \mspace{11mu} \left( \frac{YLOC}{Roll} \right)*\left( \frac{180}{PI} \right)} - {{XLOC}*\left( \frac{DEG}{30} \right)}}} & {{Eq}.\; 5} \\{{FA} = {{CFFA} - {\arcsin \mspace{11mu} \left( \frac{XLOC}{Bulge} \right)*\left( \frac{180}{PI} \right)} + {{YLOC}*\left( \frac{DEG}{30} \right)}}} & {{Eq}.\; 6}\end{matrix}$

In Eq. 5 and Eq. 6 above, the variables are defined as:

Roll=Roll Radius (mm)

Bulge=Bulge Radius (mm)

LA=Nominal Loft Angle)(° at a desired point

FA=Nominal Face Angle)(° at a desired point

CFLA=Center Face Loft Angle)(°)

CFFA=Center Face Face Angle)(°)

YLOC=y-coordinate location on the y-axis of the predetermined point (mm)

XLOC=x-coordinate location on the x-axis of the predetermined point (mm)

DEG=degree of twist in the club head being measured)(°)

By way of example, assume a golf club having a 1° twist, CFLA of 9.2°, aCFFA of 0°, a bulge of 330.2 mm, and a roll of 279.4 mm is provided,similar to Example 5 described in Table 3. In order to calculate the LA°Δ and FA° Δ at critical point P4 located at an x-y coordinate of (0 mm,15 mm), 0 mm is utilized as the XLOC value and 15 mm as the YLOC value.The DEG value is 1°. When these variables are entered into Equation 5above, a LA value of 12.277° and a FA value of 0.500° is calculated forcritical point P4.

The LA° Δ is the nominal loft at the critical point P4 minus the centerface loft. In this case, the CFLA is 9.2°. Therefore the LA° Δ is12.277° minus 9.2° which equals 3.077° as shown in Table 3 at thecritical point P4 in Example 5.

Likewise, Equation 6 yields the FA value of 0.500°. The FA° Δ is thenominal face angle, FA, at the critical point P4 minus the center faceface angle. In this case, the CFFA is 0° (which is likely always thecase). Therefore, the FA° Δ at critical point P4 is 0.500° minus 0°which equals 0.500° as shown in Table 3.

Thus, the FA° Δ and LA° Δ can be calculated at any desired x-ycoordinate by calculating the nominal FA and LA values in Equations 5and 6 above utilizing the necessary variables.

It is also possible to use the above equation to set bounds on thedesired face shape for a given head. For example, if a head has a bulgeradius (Bulge), and roll radius (Roll), it is possible to define twobounding surfaces for the desired twisted face surface by specifying twodifferent twist amounts (DEG). In order to bound the example above, wecan use a CFLA of 9.2°, a bulge of 330.2 mm, and a roll of 279.4 mm,then specify a range of twist of, for example 0.5°<DEG<1.5°. Then,preferably at least 50% of the face surface would have a FA and LAwithin the bounds of the equations using DEG=0.5° and DEG=1.5°. Morepreferably at least 70% of the face surface would have a FA and LAwithin the bounds of the equations using DEG=0.5° and DEG=1.5°. Mostpreferably at least 90% of the face surface would have a FA and LAwithin the bounds of the equations using DEG=0.5° and DEG=1.5°.

Similarly, if the target twist is, DEG=2.0°, then the upper/lower limitscould be 1.5°<DEG<2.5°, and preferably 50%, or more preferably 70%, ormost preferably 90% of the face surface would have a FA and LA withinthe bounds of the equations using those angles.

To make the upper/lower bound FA and LA equations more general for anydriver with any bulge and roll, the process would be to define theamount of twist (i.e., 1°, 2°, 3°, etc.), then determine the desiredCFLA, CFFA, Bulge and Roll, then define the upper bound equation usingthose parameters and a twist, DEG+, which is 0.5° higher than the targettwist, DEG, and a lower bound with a twist, DEG−, which is 0.5° lowerthan the target twist, DEG. In this way, preferably 50%, or morepreferably 70%, or most preferably 90% of the face surface would have aFA and LA within the bounds of the equations using DEG+ and DEG- and thedesired CFLA, CFFA, Bulge and Roll.

For example, the range of CFLA can be between 7.5° and 16.0°, preferably10.0°, the range of CFFA can be between −3.0° and +3.0°, preferably0.0°, the range of Bulge can be between 228.6 mm to 457.2 mm, preferably330.2 mm, and the range of Roll can be between 228.6 mm to 457.2 mm,preferably 279.4 mm. Any combination of these parameters within theseranges can be used to define the nominal FA and LA values over the facesurface, and ranges of twist can range from 0.5° to 4.0°, preferably1.0°.

Although the embodiments above describe a twisted face that has agenerally open (more positive) FA° Δ in the upper toe and heel quadrant,it is also possible to create a golf club head with a closed (morenegative) FA° Δ in the upper toe and heel quadrants. In other words, thetwisting direction could be in the opposite direction of the embodimentsdescribed herein.

Because the twisted face described herein has a generally more open(more positive) face angle, the topline 280, shown in FIG. 2d , mayappear more open or positive face angle to the golfer. For many golfers,this is a useful alignment feature which gives the golfer the confidencethat the ball will not fly too far let. Thus, a twisted face golf clubthat is more open has the advantage of having a more open toplinealignment appearance when the paint line of the crown ends at theintersection of the face and the crown at the topline 280.

In contrast, it is possible to have a golf club with a more negative orclosed face twist in which case the topline 280 will have a more closedor negative face angle appearance to the golfer when the paint lineoccurs at the topline 280 of the face and crown intersection.

In view of the many possible embodiments to which the principles of thedisclosed invention may be applied, it should be recognized that theillustrated embodiments are only preferred examples of the invention andshould not be taken as limiting the scope of the invention. It will beevident that various modifications may be made thereto without departingfrom the broader spirit and scope of the invention as set forth. Thespecification and drawings are, accordingly, to be regarded in anillustrative sense rather than a restrictive sense.

1. A golf club head comprising: a hosel portion, a heel portion, a soleportion, a toe portion, a crown portion, and a striking face; the hoselcomprising an adjustable head-shaft connection capable of adjusting anorientation of the club head relative to a shaft to adjust one or moreof a loft angle, lie angle, and face angle of the club head; thestriking face having a center face location; a center face verticalplane passing through the center face location and extending in afront-rear direction, the center face vertical plane extending fromadjacent the crown portion to adjacent the sole portion and intersectingwith the striking face surface to define a center face roll contour; acenter face horizontal plane passing through the center face locationand extending in a front-rear direction, the center face horizontalplane extending from adjacent the toe portion to adjacent the heelportion and intersecting with the striking face surface to define acenter face bulge contour; the striking face having a toe-crown quadrantdefined as a portion of the striking face that is toeward of the centerface vertical plane and crownward of the center face horizontal plane;and wherein the toe-crown quadrant has an average quadrant face angledifference (AQFA° Δ) of between 0.1° and 5.0° relative to the centerface location.
 2. The golf club head of claim 1, wherein the toe-crownquadrant has an AQFA° Δ of between 0.3° and 3.0° relative to the centerface location.
 3. The golf club head of claim 1, wherein the toe-crownquadrant has an AQFA° Δ of between 0.3° and 0.5° relative to the centerface location.
 4. The golf club head of claim 1, wherein the strikingface comprises: a first point in the toe-crown quadrant located at (−10mm, 10 mm); a second point in the toe-crown quadrant located at (−18 mm,12 mm); a third point in the toe-crown quadrant located at (−25 mm, 20mm); and a fourth point in the toe-crown quadrant located at (−30 mm, 15mm); wherein an average face angle difference (FA° Δ) of the first,second, third, and fourth points is between 0.1° and 5° relative to thecenter face location.
 5. (canceled)
 6. The golf club head of claim 4,wherein the average FA° Δ of the first, second, third, and fourth pointsis between 0.4° and 1.0° relative to the center face location.
 7. Thegolf club head of claim 1, wherein an average loft angle difference (LA°Δ) of the toe-crown quadrant is between 0.4° and 0.8° relative to thecenter face location.
 8. The golf club head of claim 4, where an averageloft angle difference (LA° Δ) of the first, second, third, and fourthpoints is between 0.5° and 1.5° relative to the center face location. 9.The golf club head of claim 1, wherein the striking face has a bulgeradius between 228.6 mm and 355.6 mm
 10. The golf club head of claim 1,wherein the striking face has a bulge radius between 228.6 mm and 330.2mm
 11. The golf club head of claim 1, wherein the striking face has avariable face thickness having an inverted recess in a center portion ofa back surface of the striking face.
 12. A golf club comprising: a golfclub head having a hosel portion, a heel portion, a sole portion, a toeportion, a crown portion, and a striking face; a golf club shaft; thehosel comprising an adjustable head-shaft connection capable ofadjusting an orientation of the club head relative to the shaft toadjust one or more of a loft angle, lie angle, and face angle of thegolf club; the striking face having a center face location; a centerface vertical plane passing through the center face location andextending in a front-rear direction, the center face vertical planeextending from adjacent the crown portion to adjacent the sole portionand intersecting with the striking face surface to define a center faceroll contour; a center face horizontal plane passing through the centerface location and extending in a front-rear direction, the center facehorizontal plane extending from adjacent the toe portion to adjacent theheel portion and intersecting with the striking face surface to define acenter face bulge contour; the striking face having a toe-crown quadrantdefined as a portion of the striking face that is toeward of the centerface vertical plane and crownward of the center face horizontal plane;and wherein the toe-crown quadrant has an average quadrant face angledifference (AQFA° Δ) of between 0.1° and 5.0° relative to the centerface location.
 13. The golf club of claim 12, wherein the toe-crownquadrant has an AQFA° Δ of between 0.3° and 3.0° relative to the centerface location.
 14. The golf club of claim 12, wherein the toe-crownquadrant has an AQFA° Δ of between 0.3° and 0.5° relative to the centerface location.
 15. The golf club of claim 12, wherein the striking facecomprises: a first point in the toe-crown quadrant located at (−10 mm,10 mm); a second point in the toe-crown quadrant located at (−18 mm, 12mm); a third point in the toe-crown quadrant located at (−25 mm, 20 mm);and a fourth point in the toe-crown quadrant located at (−30 mm, 15 mm);wherein an average FA° Δ of the first, second, third, and fourth pointsis between 0.1° and 5° relative to the center face location.
 16. Thegolf club of claim 15, wherein the average FA° Δ of the first, second,third, and fourth points is between 0.3° and 0.5° relative to the centerface location.
 17. The golf club of claim 12, wherein an average loftangle difference (LA° Δ) of the toe-crown quadrant is between 0.4° and0.8° relative to the center face location.
 18. The golf club of claim12, wherein the striking face has a bulge radius between 228.6 mm and355.6 mm
 19. The golf club of claim 12, wherein the striking face has abulge radius between 228.6 mm and 330.2 mm
 20. A golf club headcomprising: a hosel portion, a heel portion, a sole portion, a toeportion, a crown portion, and a striking face; the striking face havinga center face location; a center face vertical plane passing through thecenter face location and extending in a front-rear direction, the centerface vertical plane extending from adjacent the crown portion toadjacent the sole portion and intersecting with the striking facesurface to define a center face roll contour; a center face horizontalplane passing through the center face location and extending in afront-rear direction, the center face horizontal plane extending fromadjacent the toe portion to adjacent the heel portion and intersectingwith the striking face surface to define a center face bulge contour;the striking face having a toe-crown quadrant defined as a portion ofthe striking face that is toeward of the center face vertical plane andcrownward of the center face horizontal plane; wherein the striking facecomprises: a first point in the toe-crown quadrant located at (−10 mm,10 mm); a second point in the toe-crown quadrant located at (−18 mm, 12mm); a third point in the toe-crown quadrant located at (−25 mm, 20 mm);and a fourth point in the toe-crown quadrant located at (−30 mm, 15 mm);wherein an average face angle difference (FA° Δ) of the first, second,third, and fourth points in the toe-crown quadrant is between 0.3° and0.5° relative to the center face location.
 21. The golf club head ofclaim 20, wherein an average loft angle difference (LA° Δ) of the first,second, third, and fourth points in the toe-crown quadrant is between0.4° and 0.8° relative to the center face location.